EP0052878A1 - Magnetischer Keil - Google Patents

Magnetischer Keil Download PDF

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Publication number
EP0052878A1
EP0052878A1 EP19810109838 EP81109838A EP0052878A1 EP 0052878 A1 EP0052878 A1 EP 0052878A1 EP 19810109838 EP19810109838 EP 19810109838 EP 81109838 A EP81109838 A EP 81109838A EP 0052878 A1 EP0052878 A1 EP 0052878A1
Authority
EP
European Patent Office
Prior art keywords
wedge
magnetic
slots
ferrite
slot
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP19810109838
Other languages
English (en)
French (fr)
Other versions
EP0052878B1 (de
Inventor
Seiji Watabe
Motohiko Makino
Yasuhiro Sasaki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TDK Corp
Original Assignee
TDK Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by TDK Corp filed Critical TDK Corp
Publication of EP0052878A1 publication Critical patent/EP0052878A1/de
Application granted granted Critical
Publication of EP0052878B1 publication Critical patent/EP0052878B1/de
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/46—Fastening of windings on the stator or rotor structure
    • H02K3/48—Fastening of windings on the stator or rotor structure in slots
    • H02K3/487—Slot-closing devices
    • H02K3/493—Slot-closing devices magnetic
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/0018—Applying slot closure means in the core; Manufacture of slot closure means

Definitions

  • This invention relates to a magnetic ferrite wedge.
  • Magnetic wedges are in use as means for improving the efficiency of electric motors. Varied means for improving the motor efficiency have been studied and developed, and typical of them are known as the open-slot and semiopen-slot types.
  • the motors incorporating those means consist essentially of a stator and a rotor, and at least one of the opposing surfaces of the two members, usually of the stator, is formed with axially extending slots (or grooves) at regular intervals along the inner or outer periphery of the cylindrical member, the slots having windings inserted and held in place, one for each. In the opening of each slot is firmly fitted a magnetic wedge to keep the winding securely and increase the motor efficiency. In this way the copper and iron losses are decreased and the overall efficiency is improved.
  • motors run at operating frequencies from about 50 hertz up to several hundred kilohertz, most wedges have to be made of iron or steel or, for added strength against break at the time of insertion, iron powder compacts reinforced with glass fiber.
  • the present invention aims at providing a magnetic wedge free from the afore-said drawback.
  • the invention makes possible a material improvement in the operating efficiency of motors by the adoption of sintered soft ferrite as wedge material.
  • soft ferrites which may advantageously be employed for the invention are the ferrites of Mn-Zn, Mn-Zn-Fe, Ni-Cu-Zn, and Ni-Fe types. As will be explained later, these soft ferrites will have little effect in the form of powder compacts; they should always be used as sintered bodies. -The soft ferrite for use in the invention may be made in the conventional way.
  • FIG. 1 which illustrates how magnetic wedges are fitted in stator slots
  • the numeral 1 indicates a stator and 2 a rotor, the stator being the member wedged in this embodiment of the invention.
  • the inner periphery of the stator 1 has a number of keyhole-shaped slots 3 formed in an equidistantly spaced relation.
  • Each slot 3 receives part of a winding 4, and its open end facing the rotor is closed with a generally T-shaped magnetic wedge 5 of a size fit for the purpose.
  • a long stick of magnetic ferrite is easily broken by forces applied laterally across its axis.
  • the stick If directly inserted into the slot such as by hammering or machine pushing, slidingly in parallel to its long opening, the stick would be subjected to excessive forces from the surrounding wall and the winding and could crack from stresses and strains. To avoid this, the stick is inserted in place using a jig as shown in FIG. 2.
  • a metal jig to be used has twin T-heads 6 and 10 either of which can force away the winding sidewise, or into a more compact form, to provide enough space for the wedge insertion.
  • the T-heads 6, 10 are formed in one piece with a base 7 of a given width W 1 in between to constitute the jig.
  • the top of the base in the middle part of the jig serves as a holding surface 8, and the height h of the T-heads 6, 10 as measured from that surface is slightly greater than the height of the magnetic wedge 5.
  • the width W 1 of the base 7 is slightly less than the width W 2 of opening of the slot 3, and the width T 1 of the top of each T-head is slightly less than the corresponding width T 2 of the slot 3.
  • the length 1 1 of the holding surface 8 is so chosen as to exceed the length 1 2 of the stator slot.
  • the magnetic wedge 5 is placed on the holding surface 8, and the jig carrying the wedge is inserted, with its front end 11 as the guide, into the slot 3.
  • the front T-head 10 moves in the direction of the arrow, pushing the winding aside and creating a sufficient space for the accommodation of the wedge 5.
  • the wedge is thus smoothly inserted into the slot without subjection to any stress. Since the length 11 of the holding surface on which the wedge rests is greater than the length 1 2 of the slot, the jig is then pulled downward out of the stator slot, leaving the wedge behind in place within the slot.
  • the wedges were made in three types of different compositions, namely Mn 0.7 Zn 0.2 Fe 0.1 Fe 2 O 4+ ⁇ (Sintered ferrite body 1 ), Ni 0.34 Cu 0.1 Zn 0.56 Fe 2 O 4+ ⁇ (sintered ferrite body 2), and Ni 0.6 Fe 0.4 Fe 2 O 4+ ⁇ (Sintered ferrite body 3).
  • a plastic molding containing 85 % by weight of pulverized sintered ferrite (ferrite powder compact) and a glass fiber-reinforced plastic molding containing 70 % by weight of iron dust (iron dust compact) were also made. Wedges of each type were fitted in the slots of the induction motor as shown in FIG. 1, and then the motor was tested for various characteristics. Also, the motor free from such magnetic wedges was tested in the same way. The items measured were the efficiency, power factor, slip, total loss, maximum output, and maximum torque of the motor during operation under rated conditions. The results were as tabulated below. operation under rated conditions.
  • the wedges of sintered ferrite bodies 1, 2, 3 according to the invention reduced the total losses of the motors to levels lower than those with the green ferrite and iron compacts, to say nothing of the loss without the use of wedges.
  • they permitted 1 % to nearly 3 % improvements in motor efficiency over the wedge-free motor and 0.5 - 1.7 % over the motors using the ferrite powder compact wedge and iron dust compact wedge. It should be obvious to any one of ordinary skill in the art that these improvements made possible by the invention are of very great value from the viewpoint of energy saving.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Insulation, Fastening Of Motor, Generator Windings (AREA)
EP19810109838 1980-11-25 1981-11-23 Magnetischer Keil Expired EP0052878B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP164667/80 1980-11-25
JP16466780A JPS5788848A (en) 1980-11-25 1980-11-25 Magnetic wedge

Publications (2)

Publication Number Publication Date
EP0052878A1 true EP0052878A1 (de) 1982-06-02
EP0052878B1 EP0052878B1 (de) 1985-08-21

Family

ID=15797528

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19810109838 Expired EP0052878B1 (de) 1980-11-25 1981-11-23 Magnetischer Keil

Country Status (4)

Country Link
EP (1) EP0052878B1 (de)
JP (1) JPS5788848A (de)
DE (1) DE3171942D1 (de)
DK (1) DK159703C (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6674209B2 (en) 2000-12-01 2004-01-06 General Electric Company Method for increasing subtransient reactance of a generator
EP2169809A1 (de) 2008-09-30 2010-03-31 Ansaldo Sistemi Industriali S.p.A. Ferromagnetischer Keil zum Schließen von Nuten einer elektrischen Drehmaschine und Maschinenstruktur mit dem Keil
ITMI20081737A1 (it) * 2008-09-30 2010-04-01 Ansaldo Sistemi Spa Bietta ferromagnetica di chiusura delle cave di una macchina elettrica rotante e struttura di macchina che incorpora detta bietta
US20160380495A1 (en) * 2015-06-29 2016-12-29 General Electric Company Short circuit fault tolerant permanent magnet machine

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008134796A1 (en) * 2007-05-03 2008-11-13 In Motion Technologies Pty Ltd Rotor magnet positioning device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB227953A (en) * 1923-11-06 1925-01-29 Jan Arthur Kuyser Improvements in or relating to dynamo-electric machines
GB624541A (en) * 1947-05-31 1949-06-10 Frost & Co Ltd H Improvements in means for closing the winding-slots of dynamo-electric machines
GB712802A (en) * 1951-08-09 1954-07-28 Siemens Ag Improvements in or relating to slot wedges for electric machines
GB1107485A (en) * 1965-07-21 1968-03-27 Siemens Ag Improvements in or relating to the manufacture of electric machines
US3507029A (en) * 1967-10-02 1970-04-21 Fort Wayne Tool & Die Inc Apparatus for inserting coils and slot wedges into a core member
US3968556A (en) * 1975-11-07 1976-07-13 Essex International, Inc. Wedge feeding mechanism for short stroke dynamoelectric machine coil and wedge inserting apparatus

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5024962U (de) * 1973-06-29 1975-03-20

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB227953A (en) * 1923-11-06 1925-01-29 Jan Arthur Kuyser Improvements in or relating to dynamo-electric machines
GB624541A (en) * 1947-05-31 1949-06-10 Frost & Co Ltd H Improvements in means for closing the winding-slots of dynamo-electric machines
GB712802A (en) * 1951-08-09 1954-07-28 Siemens Ag Improvements in or relating to slot wedges for electric machines
GB1107485A (en) * 1965-07-21 1968-03-27 Siemens Ag Improvements in or relating to the manufacture of electric machines
US3507029A (en) * 1967-10-02 1970-04-21 Fort Wayne Tool & Die Inc Apparatus for inserting coils and slot wedges into a core member
US3968556A (en) * 1975-11-07 1976-07-13 Essex International, Inc. Wedge feeding mechanism for short stroke dynamoelectric machine coil and wedge inserting apparatus

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6674209B2 (en) 2000-12-01 2004-01-06 General Electric Company Method for increasing subtransient reactance of a generator
US6683398B2 (en) 2000-12-01 2004-01-27 General Electric Company Generator magnetic armature wedge
EP2169809A1 (de) 2008-09-30 2010-03-31 Ansaldo Sistemi Industriali S.p.A. Ferromagnetischer Keil zum Schließen von Nuten einer elektrischen Drehmaschine und Maschinenstruktur mit dem Keil
ITMI20081737A1 (it) * 2008-09-30 2010-04-01 Ansaldo Sistemi Spa Bietta ferromagnetica di chiusura delle cave di una macchina elettrica rotante e struttura di macchina che incorpora detta bietta
US20160380495A1 (en) * 2015-06-29 2016-12-29 General Electric Company Short circuit fault tolerant permanent magnet machine
US9979248B2 (en) * 2015-06-29 2018-05-22 General Electric Company Short circuit fault tolerant permanent magnet machine
GB2541781B (en) * 2015-06-29 2018-06-27 Gen Electric Short circuit fault tolerant permanent magnet machine

Also Published As

Publication number Publication date
DK159703C (da) 1991-04-15
JPS5788848A (en) 1982-06-02
EP0052878B1 (de) 1985-08-21
DK159703B (da) 1990-11-19
DE3171942D1 (en) 1985-09-26
DK463781A (da) 1982-05-26

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